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昆明城市土壤有机碳氮含量及其稳定同位素耦合关系研究

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环境化学 2024年第4期43卷 1304-1314页

作者：马锐麒温雯雯冯长涛吕娜王明果黄林培云南省高原地理过程与环境变化重点实验室云南师范大学地理学部昆明650500 云南师范大学化学化工学院昆明650500 云南省地矿测绘院有限公司昆明650218

随着城镇化的快速推进,城市土壤已成为陆地生态系统重要组成部分,不同土地利用类型土壤有机碳氮含量、稳定同位素组成分布特征及其耦合关系是了解城市土壤碳氮循环过程的重要途径.选取昆明市区受人类活动影响程度不同的公园绿地、居住... 详细信息

随着城镇化的快速推进,城市土壤已成为陆地生态系统重要组成部分,不同土地利用类型土壤有机碳氮含量、稳定同位素组成分布特征及其耦合关系是了解城市土壤碳氮循环过程的重要途径.选取昆明市区受人类活动影响程度不同的公园绿地、居住绿地、道路绿地、耕地4类土壤作为研究对象,开展0—20 cm土壤有机质碳氮元素及其同位素组成的空间分异特征与影响因素研究.结果表明,昆明城市土壤有机质含量低,有机碳(SOC)和总氮(TN)含量中值分别为6.14 g·kg^(−1)和0.55 g·kg^(−1),较全国城市土壤平均水平低27.22%(C)和28.57%(N).土壤有机碳同位素(δ^(13)C)平均值为-25.22‰±1.56‰,氮同位素(δ^(15)N)则分布范围较广,为1.22‰—10.12‰,平均值为6.55‰±1.58‰,显著高于其他自然土壤δ^(15)N值. 4类土地利用类型中,耕地土壤SOC、TN含量显著偏高,δ^(13)C和δ^(15)N值显著偏正.垂向分布上,公园绿地、居住绿地、道路绿地SOC、TN含量随土层深度的增加而降低,δ^(13)C和δ^(15)N值则呈现富集趋势,表明重同位素^(13)C、^(15)N在土壤腐殖质中富集.耕地土壤因人为耕作,理化性质分层特征不明显.昆明市较低的土壤有机质含量与城市化进程导致的土地利用类型改变、绿化年限影响的成土时间较短以及昆明市气候、土质、植被类型等多因素有关.昆明城市土壤δ^(13)C值主要受昆明C_(3)、C_(4)植被覆盖度等自然环境因素影响,而δ^(15)N值由于受城市中水灌溉影响,显著偏正于自然土壤,指示人类活动已显著改变城市土壤氮循环过程,使土壤中更富集重同位素^(15)N.不同土地利用类型土壤垂向分布特征揭示有机质的分解、转化过程会对碳、氮同位素产生分馏作用,且氮同位素分馏高于碳同位素的分馏.

关键词：城市土壤有机碳全氮碳氮稳定同位素土地利用类型昆明

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Response to paleoatmospheric CO_2 concentration of Solenites vimineus(Phillips)Harris(Ginkgophyta)from the Middle Jurassic of the Yaojie Basin,Gansu Province,China

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Science China Earth Sciences 2009年第12期52卷 2029-2039页

作者： YAN DeFei SUN BaiNian XIE SanPing LI XiangChuan wen wenwen Key Laboratory of Western China’s Environmental Systems of the Ministry of Education Lanzhou UniversityLanzhou 730000China LPS Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China

Solenites vimineus (Phillips) Harris (Ginkgophyta) specimens with well-preserved cuticles were collected from five different beds in the oil shale member of the Middle Jurassic Yaojie Formation in the Yaojie Basin, Gansu Province, northwestern China. Gross morphology and fine structures of the fossil leaves were studied, and stomatal parameters were analyzed, according to which, the paleoatmospheric CO2 concentration can be deduced as 1512-1896 ppm that would have caused an increase in mean temperature of about 6.5-7.4℃. Carbon isotopes from the fossils indicate that the carbon isotopic discrimination and water use efficiency (WUE) of S. vimineus were raised nearly obtaining the ideal physiologic state in increased CO2 concentrations and temperature conditions, suggesting that S. vimineus records the paleoenvironmental information of the Middle Jurassic Yaojie Basin and can be used for environmental reconstruction.

关键词： Solenites vimineus stomatal parameters paleo-CO_(2)concentration carbon isotopes Middle Jurassic northwestern China

Controlled Twill Surface Structure Endowing Nanofiber Composite Membrane Excellent Electromagnetic Interference Shielding

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Nano-Micro Letters 2024年第11期16卷 255-273页

作者： Dechang Tao Xin wen Chenguang Yang Kun Yan Zhiyao Li wenwen Wang Dong Wang Key Laboratory of Textile Fiber and Products(Wuhan Textile University) Ministry of EducationWuhan Textile UniversityWuhan 430200People’s Republic of China College of Chemistry Chemical Engineering and BiotechnologyDonghua UniversityShanghai 201620People’s Republic of China

Inspired by the Chinese Knotting weave structure,an electromagnetic interference(EMI)nanofiber composite membrane with a twill surface was ***(vinyl alcohol-co-ethylene)(Pva-co-PE)nanofibers and twill nylon fabric were used as the matrix and filter templates,respectively.A Pva-co-PEMXene/silver nanowire(Pva-co-PE-MXene/AgNW,PM_(x)Ag)membrane was successfully prepared using a template *** the MXene/AgNW content was only 7.4 wt%(PM_(7.4)Ag),the EMI shielding efficiency(SE)of the composite membrane with the oblique twill structure on the surface was 103.9 dB and the surface twill structure improved the EMI by 38.5%.This result was attributed to the pre-interference of the oblique twill structure in the direction of the incident EM wave,which enhanced the probability of the electromagnetic waves randomly colliding with the MXene ***,the internal reflection and ohmic and resonance losses were *** PM_(7.4)Ag membrane with the twill structure exhibited both an outstanding tensile strength of 22.8 MPa and EMI SE/t of 3925.2 dB cm^(-1).Moreover,the PM_(x)Ag nanocomposite membranes demonstrated an excellent thermal management performance,hydrophobicity,non-flammability,and performance stability,which was demonstrated by an EMI SE of 97.3%in a high-temperature environment of 140℃.The successful preparation of surface-twill composite membranes makes it difficult to achieve both a low filler content and a high EMI SE in electromagnetic shielding *** strategy provides a new approach for preparing thin membranes with excellent EMI properties.

关键词： Twill surface structure MXene/AgNW Nanofiber membrane Electromagnetic interference Flexibility and mechanical properties

Extreme drought with seasonal timing consistently promotes CH_(4) uptake through inconsistent pathways in a temperate grassland, China

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Journal of Arid Land 2024年第6期16卷 768-778页

作者： ZHANG wenwen PAN Yue wen Fuqi FU Juanjuan HAO Yanbin HU Tianming YANG Peizhi College of Grassland Agriculture Northwest A&F UniversityYangling 712100China Binzhou Institute of Technology Weiqiao-UCAS(University of Chinese Academy of Sciences)Science and Technology ParkBinzhou 256606China College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China

Methane(CH_(4))is a potent greenhouse gas that has a substantial impact on global warming due to its substantial influence on the greenhouse *** extreme precipitation events,such as drought,attributable to global warming that caused by greenhouse gases,exert a profound impact on the intricate biological processes associated with CH_(4) ***,the timing of extreme drought occurrence emerges as a pivotal factor influencing CH_(4) uptake,even when the degree of drought remains ***,it is still unclear how the growing season regulates the response of CH_(4) uptake to extreme *** an effort to bridge this knowledge gap,we conducted a field manipulative experiment to evaluate the impact of extreme drought on CH_(4) uptake during early,middle,and late growing stages in a temperate steppe of Inner Mongolia Autonomous Region,*** result showed that all extreme drought consistently exerted positive effects on CH_(4) uptake regardless of seasonal ***,the magnitude of this effect varied depending on the timing of season,as evidenced by a stronger effect in early growing stage than in middle and late growing ***,the pathways of CH_(4) uptake were different from seasonal *** drought affected soil physical-chemical properties and aboveground biomass(AGB),consequently leading to changes in CH_(4) *** structural equation model showed that drought both in the early and middle growing stages enhanced CH_(4) uptake due to reduced soil water content(SWC),leading to a decrease in NO_(3)–-N and an increase in pmoA ***,drought in late growing stage primarily enhanced CH_(4) uptake only by decreasing *** results suggested that seasonal timing significantly contributed to regulate the impacts of extreme drought pathways and magnitudes on CH_(4) *** findings can provide substantial implications for understanding how extreme droughts affect CH_(4) uptake and improve the prediction of

关键词： extreme climate greenhouse gas methane methanotrophs soil inorganic nitrogen

High-resolution single-photon LiDAR without range ambiguity using hybrid-mode imaging [Invited]

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Chinese Optics Letters 2024年第6期22卷 33-37页

作者： Xin-Wei Kong wen-Long Ye wenwen Li Zheng-Ping Li Feihu Xu Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences University of Science and Technology of ChinaHefei 230026China Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaShanghai 201315China School of Mechanical Electrical and Information EngineeringShandong UniversityWeihai 264209China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

We proposed a hybrid imaging scheme to estimate a high-resolution absolute depth map from low photon counts. It leverages measurements of photon arrival times from a single-photon LiDAR and an intensity image from a conventional high-resolution camera. Using a tailored fusion algorithm, we jointly processed the raw measurements from both sensors and output a high-resolution absolute depth map. We scaled up the resolution by a factor of 10, achieving 1300 × 2611 pixels and extending ~4.7 times the unambiguous range. These results demonstrated the superior capability of long-range high-resolution 3D imaging without range ambiguity.

关键词： single-photon LiDAR single-photon imaging hybrid-mode imaging

Time-Transgressive Nature of the Magnetic Susceptibility Record across the Chinese Loess Plateau at the Pleistocene/Holocene Transition

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Time-Transgressive Nature of the Magnetic Susceptibility Rec...

Protective effect of Fu Brick tea on high-fat diet-induced metabolic syndrome: Relevant to protecting the intestinal barrier and regulating the gut microbiota

中国科学院地质与地球物理研究所2015年度（第15届）学术年会

作者： Yajie Dong Naiqin Wu Fengjiang Li Linpei Huang wenwen wen Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences University of the Chinese Academy of Sciences Key Laboratory of Plateau Lake Ecology and Global Change College of Tourism and Geography Yunnan Normal University

The loess stratigraphic boundary at the Pleistocene/Holocene transition defined by the magnetic susceptibility(MS) has previously been assumed to be synchronous with the Marine Isotope Stage(MIS) 2/1 boundary, and approximately time-synchronous at different sections across the Chinese Loess Plateau(CLP). However, although this assumption has been used as a basis for proxy-age model of Chinese loess deposits, it has rarely been tested by using absolute dating methods. In this study, we applied a single-aliquot regenerative-dose(SAR) protocol to the 45–63 μm quartz grain-size fraction to derive luminescence ages for the last glacial and Holocene sections of three loess sections on a transect from southeast to northwest across the CLP. Based on the 33 closely spaced optically stimulated luminescence(OSL) samples from the three sections, OSL chronologies were established using a polynomial curve fit at each section. Based on the OSL chronology, the timing of the Pleistocene/Holocene boundary, as defined by rapid changes in MS values, is dated at0.5 ka, 8.5 ka and 7.5 ka in the Yaoxian section, Jingchuan and Huanxian sections respectively. These results are clearly inconsistent with the MIS 2/1 boundary age of 12.05 ka, and therefore we conclude that the automatic correlation of the Pleistocene/Holocene transition, as inferred from the MS record, with the MIS 2/1 boundary is incorrect. The results clearly demonstrate that the marked changes in MS along the southeast to northwest transect are time-transgressive among the different sites, with the timing of significant paleosol development as indicated by the MS record being delayed by 3–4 ka in the northwest compared to the southeast. Our results suggest that this asynchronous paleosol development during the last deglacial was caused by the delayed arrival of the summer monsoon in the northwest CLP compared to the southeast.

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Food Science and Human Wellness 2024年

作者： wenwen Fang Fang Zhou Kuofei Wang Shuai wen Hongzhe Zeng Hao Xu Jingyi Tang Jian-an Huang Zhonghua Liu Key Laboratory of Tea Science of Ministry of Education，National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients，Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops， Ministry of Agriculture and Rural Affairs of China， Hunan Agricultural University

This study investigated the therapeutic effects on metabolic syndrome (MetS) and the impact on the intestinal barrier and gut microbiota of Fu brick tea aqueous extracts (FTE) on metabolic syndrome (MetS) in rats fed with a high-fat diet (HFD). Here， the results showed that FTE supplement significantly reduced HFD-induced weight gain， adiposity， dyslipidemia， fasting blood glucose (PBG) increment， and non-alcoholic fatty liver disease (NAFLD). Moreover， FTE supplement resulted in a decline in lipopolysaccharide (LPS) level and attenuation of colonic inflammation and oxidative stress to protect the intestinal barrier function. FTE supplement also maintained the intestinal barrier integrity by improving histological appearance and promoting ZO-1， Occludin， and Claudin-1 protein expression levels. Meanwhile， FTE supplement alleviated the gut microbiota dysbiosis by enhancing the Firmicutes/Bacteroidetes (F/B) ratio and stimulating the colonization of probiotic bacteria such as Akkermansia， Lactobacillus， Adlercreutzia， and Bacteroides. These findings collectively suggest that Fu brick tea could alleviate MetS and Mets-associated traits with the mechanism relevant to the protection of intestinal barrier and gut microbiota regulation.

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Enhanced potency of an IgM-like nanobody targeting conserved epitope in SARS-CoV-2 spike N-terminal domain

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Signal Transduction and Targeted Therapy 2024年第6期9卷 2726-2737页

作者： Bo Liu Honghui Liu Pu Han Xiaoyun Wang Chunmei Wang Xinxin Yan wenwen Lei Ke Xu Jianjie Zhou Jianxun Qi Ruiwen Fan Guizhen Wu wen-xia Tian George F.Gao Qihui Wang College of Veterinary Medicine Shanxi Agricultural University030801 JinzhongChina CAS Key Laboratory of Pathogen Microbiology and Immunology Institute of MicrobiologyChinese Academy of Sciences(CAS)100101 BeijingChina School of Life Sciences Yunnan University650504 KunmingYunnan ProvinceChina NHC Key Laboratory of Biosafety National Institute for Viral Disease Control and PreventionChinese Center for Disease Control and Prevention(China CDC)102206 BeijingChina Savaid Medical School University of Chinese Academy of Sciences101408 BeijingChina

Almost all the neutralizing antibodies targeting the receptor-binding domain(RBD)of spike(S)protein show weakened or lost efficacy against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)emerged or emerging variants,such as Omicron and its *** suggests that highly conserved epitopes are crucial for the development of neutralizing ***,we present one nanobody,N235,displaying broad neutralization against the SARS-CoV-2 prototype and multiple variants,including the newly emerged Omicron and its ***-electron microscopy demonstrates N235 binds a novel,conserved,cryptic epitope in the N-terminal domain(NTD)of the S protein,which interferes with the RBD in the neighboring S *** neutralization mechanism interpreted via flow cytometry and Western blot shows that N235 appears to induce the S1 subunit shedding from the trimeric S ***,a nano-IgM construct(MN235),engineered by fusing N235 with the human IgM Fc region,displays prevention via inducing S1 shedding and cross-linking virus *** to N235,MN235 exhibits varied enhancement in neutralization against pseudotyped and authentic viruses in *** intranasal administration of MN235 in low doses can effectively prevent the infection of Omicron sub-variant BA.1 and XBB in vivo,suggesting that it can be developed as a promising prophylactic antibody to cope with the ongoing and future infection.

关键词： doses prevention conserved

大功率薄煤层采煤机摇臂及其关键部件力学性能分析

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机械管理开发 2022年第6期37卷 105-106,109页

作者：温文文山西新景矿煤业有限责任公司山西阳泉045000

为进一步提升采煤机在综采工作面生产的可靠性和稳定性,以MG500/1130-AWD型采煤机为研究对象,在对其基本结构组成研究的基础上,基于SolidWroks建立摇臂壳体和二轴的三维模型,并结合实际参数设置模型参数,重点对摇臂壳体和二轴的力学特... 详细信息

为进一步提升采煤机在综采工作面生产的可靠性和稳定性,以MG500/1130-AWD型采煤机为研究对象,在对其基本结构组成研究的基础上,基于SolidWroks建立摇臂壳体和二轴的三维模型,并结合实际参数设置模型参数,重点对摇臂壳体和二轴的力学特性进行仿真分析,为今后采煤机摇臂壳体和二轴的优化设计提供理论参考。

关键词：采煤机摇臂壳体二轴轴齿轮力学特性三维模型